Starting device for alternating and three-phase current motors.



M. KALLMANN, DEGD.

r. KALLMANN, ADMINISTRATBIX.

STARTING DEVICE FOR ALTERNATINGAND THREE-PHASE CURRENT MOTORS.APPLICATION FILED MAILZB, 1909.

1,127,263. Patented Feb. 2, 1915.

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Fig.1. Fig.2..

MARTIN KALLMANN, OF BER-LIN,

GERMANY, ADMIN ISTRATRIX GERMANY; PAULA KALLMANN, 0F BERLIN, OF SAIDMARTIN KALLMANN, DECEASED.

STARTING DEVICE FOR ALTERNATING AND THREE-PHASE CURRENT MOTORS.

Specification of Letters Patent.

Patented Feb. 2, 1915.

Application filed March 25, 1909. Serial No. 485,845.

To all whom it may concern Be it known that I, MARTIN KALLMANN,electrical engineer, citizen of Germany, residing at Kurfuerstendamm40/41, Berlin, (iEBI'IDIIQQ'hZLVG invented new and useful Improvementsin Starting Devices for Alternating and Three-Phase Current Motors, ofwhich the following is a specification.

According to the hereinafter described invention the device of so-calledvariationstarters described in the Patent No. 829,340 issued to thepresent applicant Aug. 21, 1906, according to which conductors of a highpositive temperature-coeflicient, for instance iron wires-or bands(variators) are inserted into the circuit of the motor to be started, isextended to alternating current and three-phase motors, while for thesekinds of motors special, suitable systems of connecting the variatorshave been used.

In Figures 1 to 8 are illustrated diagrammatically different forms ofconstruction of the invention, the main object of which is to effect thestarting and stopping of the motor merely by closing and opening thestator-circuit, therefore, as far as possible, without opening andclosing the rotor-circuit.

Fig. 1 shows the invention in its simplest form; Fig. 2 is similar toFig. 1, except that the variators are differently connected; Figs. 3 and4 show an additional resistance of low temperature coefficient, asapplied to the forms shown in Figs. 1 and 2; Fig. 5 shows the inventionso applied to a three phase motor, that the latter may be started ineither direction; Fig. 6 illustrates an arrangement for braking; Fig. 7shows a construction in which provision is made for taking care ofexcessive tension in the event of sudden reversal of the m0- tor; Fig. 8shows how the arrangement may be controlled automatically.

This is effected in Fig. 1 in the most simple and in a general way in amanner that the rotor-circuit R is closed in itself permanently-alsowhen the motor is without currentby the three variators or groups ofvariators V arranged in star connection. If the stator-switch A isclosed, the rotor starts and at first a somewhat considerable impulse isfelt in consequence of the variators being still cold. But these becomeheated in a very short time and when red-hot they reach about theeighth-fold of their initial state so that there is obtained astarting-current which is hereby automatically regulated. After sometime, for instance 2 to 15 seconds, corresponding practically with theusual starting-time, the star-shaped variation-resistance isshortcircuited at a and 0 through the switch K turning on pivot 12 andthe starting-period is terminated. This can be effected without anyconsiderable sparking, as the iron resistances made red-hot, or at leastvery hot, after being first inserted absorb with the rapidly increasingspeed of the rotor a constantly diminishing voltage in consequence ofwhich they lose their degree of heat. At the time of theshort-circuiting they possess so little resistance that on their beingswitched off, no serious sparking can occur. The advantage of thisswitching with a constantly closed rotor-circuit consists therein thatthe starting and stopping can only be effected by the stator-leads I,II, III, so that it is possible to easily regulate the motor at adistance merely by these three leads, and it even is sufficient to breakand close only two netleads, while the third can permanently lie on thestator s. The switch K can be operated by any suitable means.

Fig. 2 is in its essential features exactly similar to Fig. 1, but thevariators V are here connected in a triangle. By being able to select atwill the star or triangle connections in the rotor-circuit,differentvariator elements, which are'just at disposal, may be used.Thus, for instance, ,for a certain motor, if only variators absorbingabout 110 volts of tension are at disposal, the triangle-connectionmight be used, but if there are only those for about 65 volts atdisposal they must be put with the same motor in star-connection,provided that these tensions correspond with the supposed type of motor.The number of the parallel variator' resistances or the susceptibilityof the groups is selected according to the normal requirement of currentof the motor in the rotor-circuit, taking into consideration the desiredstarting-momentum (full load, no load and so on) and the connection used(star or triangle or the like).

Figs. 3 and 4 differ in so far from Figs. 1 and 2 as there isintercalated before each variator', for the purpose of weakening theinitial impulse, a resistance W of a small temperature-coeflicient, forinstance of nickcline. In Fig. 3 the latter is short-circuited at theend of the starting-period together with the variators through theswitch K while in Fig. 4 the switching off of therevariation-resistances V at a and 0 by the switch K turning on Z). InFigs. 3 and 4 there can at will be used again the star or triangleconnection. In practice the switching off in two steps can, as a rule,be dispensed with.

In Fig. 5 is illustrated the starting of a three-phase motor in 'bothdirections. There is effected here by the reversingswitch A an exchangeof two feeds I and II leading to the stator 8 in consequence of thecross-connection of the contacts 1 and 6, or 3 and 4, while the thirdlead III remains lying on the same terminal of the stator by means ofthe contacts 7 and 9. The leads I, II, III lead to the pivots of theswitches 2, 5 and 8. For the rest the switching 011' of the variators,to which may be joined up also constant additional resistances, forweakening the current, as will at once be seen, is elfected by theswitch K. It is evi dent that also here the starting and stopping of themotor for a self-acting reversing-starter in both directions can beeffected in the ,most simple manner by the stator alone, while thecircuit of the rotor may be kept permanently closed by the variators andother resistances, and the same variators and the same switch K serve inboth directions in the same manner.

Fig. 6 shows an arrangement for braking with alternating-current as isnot seldom done with threephase current. While the circuit of the rotor,in the star or triangle connection of the variators, does not difierfrom Fig. 5, there is here connected to the reversing-switch A of thestator-circuit which in other respects is arranged the same as in Fig.5, a reducing-resistance a: in the connections of the contact 1 with 6,3 with 4 and 7 with 9, which may consist of resistance material with asmall temperature 00- efficient, or of variators, and the object ofwhich is to weaken in the case of a sudden braking, that is to sayreversing of the switch on the contacts 1, 4 and 7 the impulse andthereby the tension acting on the variators V at the moinent of thereversal, as during-this reversal of the current for the purpose of thecounter-current braking, there occurs a considerably increased ten sionin the circuit of the rotor which might destroy the variators, which areonly intended for one direction of movement, there- -to absorb, or sonumerous fore for a normal rotor tension. Of course the startingmomentum in the opposite direction of rotation, therefore in thedirection of the action of the brake, is considerably weakened by theresistances in the stator, but may be sufficient in practice for thebraking.

In Fig. 5 such a protection-device for the sudden reversing of themovement has not been provided. Precautions have been taken here againstthe overloading of the variators during the reversing of the current,either by making a suiiiciently long pause in the disconnection of thereversingswitch A, with a simultaneous mechanical, magnetic or otherbraking-action or the variators V must be from the beginning so largewith regard to the tension they have in multiple connection, that theyare able to absorb the suddenly increased amount of energy at the momentof the rapid reversal of the motor running with nearly its full speed inthe original direction.

In Fig. 7 the following arrangement has been made for the tension of thevariators in the case of a sudden reversal of'the movement. In thenormal direction of rotation, therefore on the contacts 3, 6 and 9 ofthe switch A there are at the beginning only the variators V in therotor-circuit, as by the simultaneous contact-closing by means of A at11, 12 and 14, 15 the additional resistances W are short-circuited fromthe beginning. If, on the other hand, for the purpose of braking withthe counter-current the switch A is reversed on the contacts 1, 4 and 7,the resistances IV are no longer shortcircuited, as the secondary switchis only one-sided. For the purpose of weakening .the excessive tensionacting otherwise on the variators in the case of a sudden reversing ofthe movement, there is inserted, when the braking takes place, beforeeach variator, a protecting-resistance W of nickeline or other materialof a small temperaturecoefiicient, instead of which also an additionalvariator for each variator may be selected which is only joined up incircuit when the counter-current is switched on for the purpose ofincreasing the total susceptibility of the variators.

Fig. 8 finally shows the applicatlon of the devices, on which thehereinbefore described systems of switching are based with the use ofautomatic switching-devices in the rotorcircuit as a sample, in one formof construction. Ihe short-circuiting of the varlators, or also of theadditional resistances may be eflfected in any suitable manner.

If the arrangement is however made electrically or electromagnetically,the influencing of the automatic switches is most advantageously donefrom the stator-circuit. Thus, for instance, the switching-device maywork for a I distant switch now be fitted out in a simple manner with atime=regulator (air, fluid or other damp ing G which is connected withan electromagnetic relay Z. If the main switch A of a one-sided or of areversing-starter connects the stator-leads rection or the other, thereis joined up in the circuit, in addition to the starting-device for therotor R illustrated in the aforementioned figures, the winding Z(timerelay) by the tension-leads connected at 3 and 9, as the contact Uis closed at first. After a few seconds, which can be regulated, thearmature of the time-relay L closes atO and Y also the circuit of thewinding E of a distant switch, which now attracts through its core N thearmature Q, and closes contacts at P and T. Hereby the variators V andother resistances in the circuit of the rotor are short-circuited, andthe disconnection is hereby completed. If the core N is attracted itraises itself at the same time away from a resilient contact B, which isthereby closed and thus connects the winding E of the directly,therefore independently of the contacts 0 and Y of the time-relay to thefeeds of the stator. After closing the contact at P and'T, and after theclosing of B by the core N of the armature, the contact U is opened andthe excitation of the winding Z of the time-relay, which has now becomesuperfluous, is interrupted. The time-relay need therefore only fewseconds and may be co structed accordingly.

As will be seen, the automatic switchingdevice, consisting of a distantswitch with time-regulator, acts in the same way for both directions ofrotation of the motor.- Also here the disconnecting may take place inseveral steps, and the above described combinations with star andtriangle connec- I, II, III in one disistance, a stator tion andwith andwithout additional resistances may be used.

Similar to the hereinbefore described system of switching for a threephase-rotor is the use of variators with alternating current motors of adifferent number of phases.

claim 1. In a starting device for three ternating current motors, aclosed rotor circuit including a resistance of high positive temperaturecoefficient, means for short circuiting the latter, a stator circuit, acurrent reversing device connected therewith, a substantially constantresistance in the rotor circuit, and means associated with the reversingdevice for controlling such constant resistance.

2. In a starting device for three phase motors, a closed rotor circuit,a resistance of high positive temperature coeflicient therein, means forshort circuiting such resistance, a stator circuit, a current reversingdevice connected therewith, a substantially constant resistance, andmeater in the circuit first mentioned when the current is reversed.

3. In a starting device for three phase motors, a closed rotor circuit,a resistance of high positive temperature coefiicient therein, means forshort circuiting such recircuit, a current reversing device connectedtherewith, and-means for reducing the tension on the resistance when thecurrent is reversed.

In testimony whereof I have name to this specification in the twosubscribing witnesses.

MARTIN KALLMANN.

phase alsigned my presence of Witnesses HENRY HAsPER, WOLDEMAR Ham.

